1. Field of the Invention
The present invention relates to the protection of a wellhead. More particularly, the present invention relates to the support of subsea structures at the wellhead. More particularly, the present invention relates to techniques for assuring that the subsea structure does not deflect or bend to such an extent as to damage the wellhead.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
In the exploration for hydrocarbons and for the production of hydrocarbons, it is necessary for various subsea structures to be affixed to the wellhead. The subsea structures can include items such as capping stacks, blowout preventers, Christmas trees, and other equipment. The subsea structures are often quite heavy. As such, if the wellhead is canted at a slight angle to horizontal or if the subsea structure is applied to the wellhead at an angle that is offset from vertical, undesirable moments can be applied to the wellhead.
Such subsea structures are becoming increasingly heavy in view of the pressures encountered by the well. Since heavier structures are being applied to the wellhead, there is a possibility for significant moments to be applied to the wellhead. In other circumstances, wellheads are often improperly installed so that they tend to have a top surface that is angularly displaced from being perfectly horizontal. As such, whenever a subsea structure is applied to such an offset wellhead, the subsea structure will be angled slightly to one side or another. Once again, the weight applied by the subsea structure to such an angularly offset wellhead can create undesirable moments to the wellhead.
Under certain circumstances, when extreme forces are applied to the wellhead, the wellhead can be significantly damaged. Procedures are not available for effectively repairing the wellhead after damage as occurred thereto. In other circumstances, when the wellhead is significantly damaged, there is a possibility of a blowout. As such, relief wells would be required, in order to seal the well. Additionally, if a blowout should occur, undesirable release of hydrocarbons into the subsea environment would occur. As such, there is a significant need for protecting the integrity of a wellhead in a subsea location.
In the past, various patents have issued for techniques for protecting the integrity of the wellhead. For example, U.S. Pat. No. 7,389,820, issued on Jun. 24, 2008 M. A. Day, describes a blowout preventer positioning system. This blowout preventer positioning system includes a mast that is functionally connected away from the frame assembly and a carriage functionally connected to the mast. The carriage is adapted to carry and support a blowout preventer in a manner such that the blowout preventer might be moved along an angular path along a plurality of linear paths. The system can include a mechanism for rotating the blowout preventer along a first rotational path. The system further includes a mechanism for rotating the blowout preventer along a second rotational path.
U.S. Pat. No. 8,261,840, issued on Sep. 11, 2012 to J. C. T. Parlee, describes a system for the alignment of a blowout preventer stack so as to facilitate the use of a rotating control mechanism. The alignment system includes at least one alignment device positioned between a pair of flanges. The alignment device has a greater thickness on one side of the alignment device that on an opposite side of the alignment device. The system includes a method of producing a relative angular offset between a first flange and a second flange which can include positioning at least one alignment device between the first and second flanges and then securing the alignment device between the first and second flanges so as to produce an angular offset. The method of aligning an axis of a blowout preventer stack with a rig floor can include positioning at least one alignment device between a first flange and a second flange of the blowout preventer stack, securing the alignment device between the first and second flanges, and securing the alignment device between the first and second flanges to produce an angular offset of the second flange relative to the first flange.
U.S. Patent Publication No. 2010/0240373, published on Sep. 27, 2012 D. Devilleger, discloses a method for the in situ repair of a wellhead base flange. At least one layer of polymerizable composite material is applied to a damaged surface, an elastic seal is placed on the layer of composite material, and a reinforcing collar is pressed against the seal on the surface of the flange covered with the composite material. The arrangement of an in situ repair of a base flange of a wellhead includes at least one layer of the polymerized composite material on a damaged surface, an elastic seal on the composite material, and a reinforcing collar pressing the seal against the damaged surface.
U.S. Patent Publication No. 2013/0206419, published on Aug. 15, 2003 to Hallundbadek et al., discloses a blowout preventer and launcher system for being mounted on a wellhead. The system includes a plurality of valves arranged in fluid communication with each other so as to be connected to form a tubular pipe. The system includes a launcher system, a well intervention module, a well intervention system and a well system.
It is an object of the present invention to provide a system and method for protecting the integrity of a wellhead which serves to avoid undesired moments between the subsea structure and the wellhead.
It is another object of the present invention to provide a system and method for protecting the integrity of a wellhead which serves to avoid damage to the wellhead.
It is another object of the present invention to provide a system and method for protecting the integrity of a wellhead that assures that the structure attached to the wellhead will remain in a stationary position throughout the hydrocarbon exploration and production activities.
It is still further object the present invention to provide a system and method for protecting the integrity of a wellhead which is easy to use, easy to deploy, easily implemented and relatively inexpensive.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.